1. Field of the Invention
The invention relates to a clamp device, more particularly to a clamp device suitable for maintaining a tightened state of a string, such as a shoestring.
2. Description of the Related Art
Referring to FIG. 1, a conventional clamp device for a string 3 is shown to include a stationary member 1 and a locking member 2. The stationary member 1 has a notched upper portion 101, and a lower portion formed with a string hole 102 therethrough. The string hole 102 is confined by a hole-confining wall 103. The locking member 2 is generally U-shaped in cross-section, and has an upper pivot portion 201 extending into the notched upper portion 101 and connected pivotally to the stationary member 1, a lower restricting portion 202 extendable into the string hole 102, and an operating projection 203 formed between the pivot and restricting portions 201, 202. The restricting portion 202 has a lower clamping side 204 disposed to confront the hole-confining wall 103 and formed with a set of teeth 205.
In use, after the string 3 is extended through the string hole 102, the locking member 2 can be pivoted relative to the stationary member 1 to extend the restricting portion 202 into the string hole 102. At this time, the teeth 205 on the restricting portion 202 engage the string 3 and force the string 3 against the hole-confining wall 103, thereby preventing movement of the string 3 in the string hole 102. Thereafter, when the locking member 2 is pivoted relative to the stationary member 1 to extend the restricting portion 202 out of the string hole 102, the teeth 205 on the restricting portion 202 cease to engage the string 3 so as to permit movement of the string 3 in the string hole 102.
The following are some of the drawbacks of the conventional clamp device:
1. When the clamp device is applied to a shoestring, repeated pivoting movement of the locking member 2 is required to adjust a position of the shoestring before the shoestring can be maintained at a tightened state.
2. The presence of the teeth 205 on the restricting portion 202 can damage the surface of the string 3, thereby shortening the service life of the string 3.
3. Because the locking member 2 is pivoted with the use of the operating projection 203, the overall size of the clamp device should be relatively large to facilitate pivoting operation of the locking member 2.
Therefore, the object of the present invention is to provide a clamp device, which is suitable for maintaining a tightened state of a string, which can be easily operated, which does not damage the string, and which has a relatively small size.
According to the present invention, a clamp device is adapted for use with a string, and comprises a housing, a pair of clamp members, and an operating unit.
The housing confines an operating space, and is formed with a string inlet hole and at least one string outlet hole that are communicated with the operating space. The string inlet hole has a first hole axis, and a pair of first hole edges opposite to each other in a first direction transverse to the first hole axis.
Each of the clamp members, which are disposed in the operating space, has a pivot portion and a clamping portion connected to the pivot portion. The pivot portion of each of the clamp members is disposed adjacent to a respective one of the first hole edges of the string inlet hole, and is pivotally retained in the housing to permit pivoting movement of the clamp members about a respective pivot axis that extends in a second direction transverse to both the first direction and the first hole axis. The clamping portion of each of the clamp members extends from the pivot portion toward the first hole axis, and has a first side face, a second side face that is opposite to the first side face in a third direction transverse to the first and second directions and that is disposed to confront the string inlet hole, and an inclined end face that is remote from the pivot portion and that extends from the first side face to the second side face. The clamp members are pivotable so as to move the clamping portions thereof toward each other from are leasing position to a clamping position, where the inclined end faces of the clamping portions of the clamp members cooperate to form a clamping space that is communicated with the string inlet hole, that diverges along the first hole axis in a direction away from the string inlet hole, and that has a wider section and a narrower section between the wider section and the string inlet hole. The clamping portion of each of the clamp members is formed with a stop block that extends from the inclined end face and that is formed with an inclined stop face for abutting against the inclined end face of the clamping portion of the other of the clamp members so as to limit movement of the clamping portions of the clamp members from the releasing position to the clamping position.
The operating unit is connected to the clamp members, and is operable so as to pivot the clamp members for moving the clamping portions of the clamp members from the clamping position to the releasing position.
When the string is extended through the string inlet hole, between the inclined end faces of the clamping portions of the clamp members, and out of the at least one string outlet hole, and when the clamping portions of the clamp members are moved to the clamping position, the string is clamped by the inclined end faces of the clamping portions of the clamp members such that movement of the string in a direction toward the string inlet hole is prevented while movement of the string in an opposite direction away from the string inlet hole is permitted.